1. Field of Invention
The invention generally relates to devices for transporting a recording medium from one processing step to a subsequent processing step, and more particularly to a device for conveying paper between two printers, which are arranged in parallel.
Description of Related Art
It is well known to operate two printers in tandem mode, if both sides of a paper are to be printed. In such a tandem configuration, the paper is output from a first printer, the xe2x80x9cupstreamxe2x80x9d printer, and fed into the second printer, the xe2x80x9cdownstreamxe2x80x9d printer. For duplex printing, the paper is turned before being fed into the downstream printer. Usually, the turning is done by a duplex paper path device which is located in the paper path between the two printers.
Depending on the arrangement of the printers, the tandem configuration may be an xe2x80x9cLxe2x80x9d-shaped configuration, where the two printers are oriented perpendicular to each other, an xe2x80x9cinlinexe2x80x9d configuration, where the two printers are arranged one behind the other, and a xe2x80x9cparallelxe2x80x9d configuration, where the two printers are located side-by-side substantially parallel to each other. Usually, the duplex paper path devices are adapted to be used exclusively for one of these arrangements. For example, a paper path device for an L-shaped printer configuration cannot be used for an inline or a parallel configuration.
U.S. Pat. No. 3,548,783 discloses a duplex paper path device for two printers in an L-shaped configuration. With this device, the paper is driven through a guide means in the form of a hollow, curved guide track. In the guide means, the direction of movement of the paper is changed and the paper is inverted while moving from the upstream printer to the downstream printer. Although the device disclosed in U.S. Pat. No. 3,548,783 allows for a reversal of the direction of movement of the paper, it does not allow for any additional flexibility, such as bypassing one of the two printers or operating in simplex mode, i.e. without turning the paper.
U.S. Pat. No. 5,457,179 discloses a turnover device for continuous feed printers in an inline configuration, where the upstream printer is located in front of the downstream printer. Thus, with the device known from U.S. Pat. No. 5,457,179 the feed direction of the paper upon entry in the turnover device is the same as upon leaving the turnover device. Due to the inline arrangement of the printers, it is difficult to bypass one of the printers, if this printer should not be not available because of e.g. maintenance or repair. Thus, the flexibility of the configuration disclosed in U.S. Pat. No. 5,457,179 is not sufficient for today""s requirements.
To increase flexibility, the parallel configuration of the printers may be used. Such an arrangement allows operation of the two printers independently in simplex mode. In addition, both printers can be coupled in tandem mode to perform duplex printing. Furthermore, it is comparatively easy to bypass one of the printers.
For a parallel printer configuration, parallel duplex paper path devices are known that comprise two turning sections, which cooperate to change the feed direction and to turn the paper.
With the known parallel duplex paper path devices, however, several problems exist. For example, a rearrangement of the paper path, e.g. an inversion of the feed direction requires major efforts in rearranging and adjusting the components of the paper path device. Thus, the known parallel paper path devices do not allow much flexibility in altering the series of processing steps. Further, at high paper velocities, the paper tends to build up oscillations and its position tends to drift laterally, so that a paper break is likely to occur. Finally, use of heavy paper results also in a high likelihood of a paper break with the known devices.
Given the problems of the existing parallel duplex paper path technologies, there is a need to provide a device which allows for an easy rearrangement of the paper path and thus leads to greater flexibility.
Further, there is need to provide a parallel paper path device which is capable of processing paper at high velocities without increasing the risk of paper breaks. Such a device would allow for a more efficient processing of paper at lower overhead costs.
Finally, there is need to provide a parallel paper path device which is capable of being operated with a wide variety of paper types.
Various exemplary embodiments of this invention separately provide a parallel duplex paper path device configured for feeding a recording medium along a feed direction from a first printing device to a second printing device, the second printing device being arranged substantially in parallel to the first printing device, the paper path device comprising at least two turning stations, the turning stations cooperating to turn the recording medium and to change the feed direction of the recording medium, wherein the turning stations are configured symmetrically.